Confidence Intervals

Which calculator function should be used to construct a confidence interval to estimate a population proportion?

• 1-PropZint

• Z-Interval

• T-Interval

Which calculator function should be used to construct a confidence interval to estimate a population mean? (Assume the population SD is known)

• 1-PropZint

• Z-Interval

• T-Interval

Which calculator function should be used to construct a confidence interval to estimate a population mean? (The population SD is unknown)

• 1-PropZint

• Z-Interval

• T-Interval

• 4

• 7

• 10

• 14

• 2

• 8

• 10

• 12

• 8

• 42

• 50

• 58

• 10

• 35

• 45

• 55

• We are 95% confident the true population mean lies between 10 and 30.

• There is a 95% chance the true population mean lies between 10 and 30.

• 95% of samples will have a mean between 10 and 30.

• The true population mean lies between 10 and 30 95% of the time.

Which of the following is true?

• Increasing the sample size makes a confidence interval wider.

• Increasing the sample size makes a confidence interval narrower.

• Decreasing the sample size makes a confidence interval narrower.

• Decreasing the sample size has no affect on the width of a confidence interval.